1 • Agriculture
2 • Suburb expansion
3 • Timbering
4 • Mining

During the 1800s, the U.S. gave up much of its Eastern forests to agriculture, but then started to make a comeback during the early 1900s. Thereafter, according to a study published in BioScience, between 1973 and 2000, Eastern forests lost 3.7 million hectares or 4.1% of their total, primarily in the southeastern plains. Read more here.